The farming industry has greatly evolved over the past several decades, going from primarily outdoor based family farms to indoor corporate run facilities. For example, swine are typically kept in a barn environment where a plurality of pens are provided in side by side relation. Typically the flooring of the facilities are slated so that swine feces can be pushed between slats by the swine to a compartment below. In this manner the facilities house numerous swine indoors without access to the outside.
As a result, artificial lighting is a main source of lighting for the swine, whether incandescent, LED, high pressure sodium, compact fluorescent or the like. As scientist have studied animals, such as chickens, turkeys, swine, cows and the like under artificial light the scientist have come to understand not only how animals see light as compared to humans, but also the effects that characteristics of light have on different animals. In particular, scientist have recognized that photoperiod or the modulation of light to animals is important. Swine studies exist showing that swine raised under continuous darkness for 24 hours were less active than swine raised under a modulated 12 hours of dark and 12 hours of light. Meanwhile swine under 24 hours of light were most active, but also showed increased levels of stress and thus the pigs welfare was considered to be affected by the presence of continuous darkness or light.
Similarly, another characteristic of light shown to affect animals is the irradiance or intensity of light. For example, tests in swine show that piglets raised under 2-6 or even 10 lux do not gain as much weight as compared to 70-100 lux light whereas 2500 lux light showed weight loss. Meanwhile in another test on piglets 50 lux light gave improved health and improved immune status as compared to 10, 20 40 and 120 lux light. So again, intensity of light is another light characteristic known to affect animals and swine.
A final factor that affects animals, including swine is the spectrum or color of light. Tests on swine show that use of red wavelength light results in heavier bodyweight and increased daily gain compared to UV, cool white or even daylight. From studies swine appear to preferred dark over light, especially during sleep and dark light reduces aggressive behavior in swine. In addition tests currently show that pigs struggle to detect light sources above 600 nanometers (nm) and are thus not overly sensitive to red lights, compared to enhanced sensitivity in the blue light spectrum.